Juice extractors

In one extractor (FMC Inc.), the fmit is located between two cups having sharp-edged metal tubes at their base. The upper cup descends and the many fingers on each cup mesh to express the juice as the tubes cut holes in the top and bottom of the fmit. On further compression, the rag, seeds, and juice sacs are compressed into the bottom tube between the two plugs of peel. A piston moves up inside the bottom tube forcing the juice through perforations in the tube wall. A simultaneous water spray washes the peel oil expressed during extraction away from the peel as an oil—water emulsion the peel oil is recovered separately from the emulsion. 

In another extractor (Automatic Machinery and Electronics Inc. (AMC)) the individual fmits are cut in half as they pass a stationary knife. The halves are oriented in a vertical plane, picked up by synthetic mbber cups, and positioned across plastic serrated reamers revolving in a synchronized carrier in a vertical plane. As the fmit halves progress around the extractor turntable, the rotating reamers exert increasing pressure and express the juice. The oil and pulp contents in the juice increase with greater reaming pressure. The recoverable oil is removed in a separate step prior to juice extraction. Needle-sharp spikes prick the peel of the whole fmit, releasing oil that is washed away with water and recovered from the oil—water emulsion. 

Lemon and Lime Juice. Lemons and Persian limes can be extracted using the same PMC and AMC extractors described above. The juice can be concentrated in a TASTE evaporator, an APV Crepaco, Inc. evaporator, or other types of evaporators (13). Although lime juice, and especially lemon juice, are widely used as condiments on food, the bulk of concentrated juice is used to make frozen concentrated lemonade and limeade. Prozen... 

Extractor - the extractor is shown in Fig. 8.7, and the means of attaching the small torque wrench in Fig. 8.8. Ideally it should be constructed from stainless steel, but we only used a stainless steel threaded rod or studding (10 X % in, 11 t.p.i., or 254 x 15.9 mm), and the rest was machined from brass. The silage juice should not remain in contact with the brass for long, however, because the brass will be attacked by the acids. The dimensions... 

Fig. 8.8. Attachment of torque wrenoh to silage juice extractor by means of a socket.

The detailed procedure of starch isolation from potato tubers is as follows. Potato tubers (10 kg) are washed, peeled, sliced into 2-3 cm cubes, and soaked in distilled water containing 20 mM sodium bisulfite and 10 mM citric acid for 2 hours to prevent darkening. The cubes are then disintegrated using a centrifugal juice extractor, the pulp is suspended in 6 L of distilled water and passed through the extractor again, and starch milk is collected. The milk is allowed to sediment for 30 minutes the supernatant and the suspended solids are removed by decantation, and the... 

Control of Juice Bitterness. A number of advances have been reported in this field since it was last reviewed (3). A commercial application of the cellulose acetate adsorption technique for the removal of limonin from citrus juices was undertaken (49). New sorbent gel forms of cellulose esters for adsorption of limonin were developed (50). Knowledge was gained that limonoids are biosynthesized in citrus leaves and translocated to the fruit (12) and that specific bioregulators can inhibit accumulation of XIV in citrus leaves (15). Additional studies were carried out on the use of neodiosmin to suppress limonin and other types of bitterness (30,51). The influence of extractor and finisher pressures on the level of limonin and naringin in grapefruit juice was reported (34). Also, further studies were conducted on the microbial sources and properties of limonoate dehydrogenase (52), the enzyme that converts XIV to XV and can be used to prevent limonin from forming in freshly expressed citrus juices (53). 

Extractor designs that minimize squeeze pressure and juice contact time with the albedo will produce grapefruit juices with... 

Extraction and finisher pressures can greatly influence the flavonoid content of citrus juices. Generally, as the fruit is squeezed harder more juice is recovered. However, excessive extractor pressures produce juice of a lower quality (35). As shown in Figure 8, grapefruit flavanone glycoside concentrations increase with increasing extractor pressures. In the early portion of the season almost twice as much naringin was obtained under hard squeeze conditions than was obtained with the soft squeeze. The effect of finisher pressure is not as clear, and is dependent on the composition of the raw juice which, in turn, is dependent on the type of extractor used. 

Thus, the type of extractor, extractor pressure, juice pulp contact time as well as ultimate juice pulp content will all alter the amount of flavanone glycosides found in the juice. 

Juice extractors differ in design, but all are fast, rugged, easy to clean, and adjustable to accomodate fruit of different sizes. Prior to the invention of automatic extractors, the rotary juice press was in common use, and is still used commercially in many parts of the world, principally Italy, Spain, South America. 

The FMC In-Line Extractor is widely used in the domestic industry, most particularly in Florida, because it can effect simultaneous recovery of both juice and oil. A five-headed extractor can process from 325 to 500 fruit/minute. The extractor consists of a bottom cup, into which the fruit is fed, and an upper cup that meshes with the bottom as circular plugs are cut from the top and bottom of the fruit. The fruit in the bottom cup is compressed as the upper cup descends and juice and other fruit components are forced through the bottom plug into a strainer tube. The contents of the strainer tube, rag, seeds, and cell sacs, are squeezed between the top and bottom plugs resulting in almost complete extraction of juice and, in essence, a first-finishing operation since the plug (seeds, pulp, and peel) is separated from the juice. As the fruit is squeezed in the cup, peel oil expressed from the flavedo and small pieces of peel are washed into a conveyer by a water spray that surrounds the extractor cup. The valuable oil is recovered from the oil/water slurry. 

Several types of Brown extractors are used in the citrus industry throughout the world. The Model 400 produces a juice that is low in peel oil content and high in juice quality. The fruit is halved and the juice removed by a rotating reamer that exerts pressure to effect extraction. 

The Brown Model 700 Extractor operates in a manner similar to the Model 400 and produces juice of the same high quality with low oil content. It expresses the juice from about 700 fruit/min. compared to the 350 fruit/min. that can be processed by the Model 400. 

In the finishing operation, seeds are removed from the juice and the pulp content is lowered. As with extractors, finishers vary in design. The two types most commonly used are the screw-type and the paddle-type. In both designs, separation is accomplished by a cylindrical perforated screen. Juice and a controlled amount of insoluble solids or fine pulp pass through the screen while the remainder of the solids is discharged at the end of the finisher. The size of the screen perforations determines the size of the solid particles that remain with the juice. The juice extractor and finisher are employed in tandem to control the characteristics of the processed juice, but they also affect the juice yield and quality. The juice characteristics controlled by these operations include the pulp content and size, and oil content. 

Shoulders or peaks were observed at 465, 443 and 425 nm of the visible spectrum (due mainly to the carotenoids present) and 325, 280 and 245 nm of the ultraviolet spectrum (due mainly to polyphenols, flavonoids and ascorbic acid, respectively). Absorbance of the maxima peaks obeyed Beer s law while the 443 325 nm absorbance ratios remained essentially constant. When fruit extractor pressures were increased, the UV absorbance of the resulting juice increased and the 443 325 nm absorbance ratio decreased. Spectra of alcoholic solutions of the rag and albedo components... 

Weeds host pathogens and nematodes and use soil nutrients. One example is pigweed, a luxuriant extractor of soil nitrogen that causes nitrate deficiencies in the sugarcane plant. Weedy grasses serve as an alternate hosts and reservoirs for systemic viruses, and they harbor insects that carry diseases to sugarcane. Rats find shelter in weedy fields. Because stalk juice alone does not provide an adequate diet, rats are attracted to weed seeds as a source of protein. 

In many cases mash pumps are used to pump the crushed fruit to the juice extractors, mash heaters or other equipment, resulting in further comminution. 

Most of the recent literature in this field is concerned with synthetic organic reactions, supramolecular chemistry and crystal engineering. However, solvent free approaches can also be used in the extraction of natural products, although less information is available in the mainstream literature. Juice extractors can be used to afford aqueous solutions of biologically active compounds from undried plant material. An extract of Capsicum annum L. was recently prepared in this way, and then used in the green synthesis of silver nanoparticles. The actual synthesis of the nanoparticles was conducted in the aqueous phase and therefore this work will not be discussed further here. However, this solvent free approach to extraction is probably worthy of greater representation in the green chemistry literature. 

The current citrus industry uses oil extraction machinery associated with the specific type of juice extractor in use. In general, peel oil extraction is carried out with Food... 

Only the EMC extractor (see Eigure 3.9-3.10) and recently, some similar machines from FOMESA (7) and OIC (8) allow a simultaneous collection of rasped peel for oil recovery and juice in separate streams. The juice passes from the extractor to a so-called finisher to remove the coarse pulp particles. Then the juice can be bottled as fresh juice or it can be used for the production of juice concentrate. If necessary, the pulp content of the juice can be further reduced by centrifugation, using so-called desludger type centrifuges (AEEA EAVAE and TETRA PAK (9), WESTEAEIA SEPARATOR (10), etc.). 

The pulp wash liquid from citrus fruit contains a higher amount of pectin than the single strength juice from the juice extractors. In most cases it must be treated enzymatically to achieve a sufficiently high concentration in the evaporator. In order to aid the concentration it is also commonly practised to centrifuge the liquid prior to evaporation to remove some or most of the insoluble solids from the liquid. 

Freshly squeezed juice for immediate consmnption with no heat treatment at all. The juice is extracted in small extractors in the presence of the customer in super markets, restaurants or road stands and it is consmned immediately. 

For the production of freshly squeezed citrus juices on a commercial basis FMC (Food Machinery Corporation) (2) has developed an improved extractor, the so-called Low Oil Extractor , which releases as little peel oil as possible into the juice. With this extractor type an oil content of the juice of below 0.03-0.035% is achieved. Juices containing higher oil levels taste unbalanced and harsh. 

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